The present invention relates to moisture curable organopolysiloxanes having terminal 1,3-dicarbonyl cyclic organosiloxy units.
Prior to the present invention, one package moisture curable organo polysiloxane compositions consisting essentially of chemically combined units of the formula, ##STR1## where R is a monovalent organic radical, generally had an organo silyl functional unit sensitive to atmospheric moisture, such as silylacyloxy unit, a silylketoximato unit, silylaminoxy unit, etc. These moisture sensitive organopolysiloxane compositions were generally maintained as a pigmented moisture-free reinforced mixture in a moisture resistant collapsible tube. Cure of the flowable organopolysiloxane was effected when the flowable mixture was applied onto a substrate under atmospheric conditions. In some instances it took several hours before the mixture attained a tack-free condition while in other situations the cure of the mixture was accompanied by an unpleasant amine odor or acid odor, such as acetic acid. In other situations, for example, when the organopolysiloxane contained chemically combined silylketoimato units, corrosion and metallic surfaces often occurred.
It would be desirable to overcome the aforementioned undesirable shortcomings of one package room temperature vulcanizing organopolysiloxane compositions by providing a one package organopolysiloxane composition capable of being converted from a flowable state to an elastomeric state upon exposure to atmospheric moisture to produce a tack-free elastomer within about one hour or less and cured organopolysiloxane elastomer within 24 hours without the generation of amine or acid byproducts causing undesirable odor and metal contamination.